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      <title>TreeMap如何实现排序 - 交互式测验</title>
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          <div class="quiz-container">
            <div class="quiz-header">
              <h1>TreeMap如何实现排序 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
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  {
    "question": "TreeMap 能够自动对其键进行排序，其底层依赖于哪种核心数据结构来保证高效的 O(log n) 操作时间复杂度？",
    "options": [
      "哈希表 (Hash Table)",
      "红黑树 (Red-Black Tree)",
      "双向链表 (Doubly Linked List)",
      "B+树 (B+ Tree)"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档中明确指出，TreeMap 的实现基于红黑树（Red-Black Tree）。红黑树是一种自平衡的二叉搜索树，它通过特定的旋转和变色操作来维持树的平衡，从而保障了查找、插入、删除操作的平均时间复杂度为 O(log n)。",
    "source": "文档中「TreeMap如何实现排序」和「3. 底层排序实现：红黑树」部分",
    "hint": "文档提到这种数据结构是一种“平衡二叉树”，能够通过特定的旋转和变色操作维持平衡。"
  },
  {
    "question": "当向一个 TreeMap 中添加元素时，它主要通过哪两种机制来确定键的排序顺序？",
    "options": [
      "键对象的 hashCode() 和 equals() 方法",
      "键对象的自然顺序（实现 Comparable 接口）或在构造时传入的自定义比较器（实现 Comparator 接口）",
      "元素的插入顺序和哈希值",
      "元素的内存地址和垃圾回收状态"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档在「TreeMap排序机制」一章中清晰地说明了其排序机制分为两种：自然顺序排序（键实现 Comparable 接口）和使用比较器排序（在构造 TreeMap 时传入一个 Comparator 对象）。TreeMap 会优先使用构造时传入的 Comparator。",
    "source": "文档中「TreeMap排序机制」部分",
    "hint": "文档将排序机制主要分为两大类：一种是对象本身就具备的比较能力，另一种是外部指定的比较规则。"
  },
  {
    "question": "在自定义 Comparator 时，其核心方法 `compare(obj1, obj2)` 的返回值有特定含义。如果该方法返回一个负整数，代表什么？",
    "options": [
      "表示 obj1 大于 obj2",
      "表示 obj1 小于 obj2",
      "表示 obj1 等于 obj2",
      "表示比较操作出现异常"
    ],
    "correctAnswerIndex": 1,
    "explanation": "根据 Comparator 接口的约定，`compare(o1, o2)` 方法的返回值规则是：返回负整数表示第一个参数小于第二个参数；返回零表示两者相等；返回正整数表示第一个参数大于第二个参数。这是实现自定义排序的基础。",
    "source": "文档中「比较器的使用」-「1. Comparator的基本作用」部分",
    "hint": "compare() 方法的返回值约定了三个范围：负数、零和正数，分别对应小于、等于和大于的关系。"
  },
  {
    "question": "根据文档，如果一个 Comparator 的设计不当，导致数据在红黑树中分布极不均匀（例如，形成类似于链表的倾斜结构），TreeMap 的查找效率会发生什么变化？",
    "options": [
      "查找效率会从 O(log N) 退化到 O(N)",
      "查找效率不受影响，因为红黑树总能自平衡",
      "查找效率会从 O(log N) 提升到 O(1)",
      "查找效率会退化到 O(N^2)"
    ],
    "correctAnswerIndex": 0,
    "explanation": "文档在分析比较器对查找效率的影响时指出，理想的比较器能让树保持平衡，确保 O(log N) 的效率。但如果比较器导致数据分布偏斜，树的高度可能接近于节点总数 N，这会使查找效率从对数时间复杂度退化为线性时间复杂度 O(N)。",
    "source": "文档中「比较器对查找效率的影响」-「2.2 偏斜的数据分布」部分",
    "hint": "当树的结构变得“倾斜”时，其高度会接近于元素的总数 N，导致查找性能急剧下降，类似于遍历一个链表。"
  },
  {
    "question": "如果需要实现多级排序（例如，先按年龄排序，年龄相同时再按姓名排序），可以使用 Comparator 接口的哪个方法来链式组合多个排序条件？",
    "options": [
      "reversed()",
      "chaining()",
      "thenComparing()",
      "andThen()"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档中的示例明确展示了如何使用 `thenComparing()` 方法来组合多个排序条件。首先使用 `Comparator.comparing()` 定义主要排序规则，然后链式调用 `thenComparing()` 添加次要排序规则。",
    "source": "文档中「比较器的使用」-「4. 多个排序条件：thenComparing()」部分",
    "hint": "文档中有一个示例，它将 `comparing(Person::getAge)` 和另一个方法组合在一起，以实现“年龄相同则按名字排序”的逻辑。"
  },
  {
    "question": "在使用自定义 Comparator 时，文档强调了 `compare()` 方法的实现应与键对象的哪个核心方法保持一致性，以避免 TreeMap 出现非预期的行为？",
    "options": [
      "hashCode() 方法",
      "equals() 方法",
      "toString() 方法",
      "clone() 方法"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档的“自定义排序时的注意事项”部分特别指出，`compare()` 和 `equals()` 方法应当保持一致。即，如果 `compare(o1, o2)` 返回 0，那么 `o1.equals(o2)` 也应该返回 true。不一致的实现可能导致 TreeMap 的行为不符合预期，例如可能包含 `compare` 认为相等但 `equals` 认为不相等的多个键。",
    "source": "文档中「5. 自定义排序时的注意事项」部分",
    "hint": "该注意事项中提到了两个方法，一个是 `compare()`，另一个是 Java 中用于判断两个对象是否相等的核心方法。"
  },
  {
    "question": "当一个 TreeMap 的键类型既实现了 `Comparable` 接口（定义了自然顺序），又在创建 TreeMap 实例时传入了一个 `Comparator` 对象，那么 TreeMap 将会采用哪种排序规则？",
    "options": [
      "使用键的 `Comparable` 实现进行排序",
      "抛出编译时异常，因为排序规则冲突",
      "交替使用两种排序规则",
      "使用传入的 `Comparator` 对象进行排序"
    ],
    "correctAnswerIndex": 3,
    "explanation": "文档明确说明，如果创建 TreeMap 时指定了 Comparator，那么 TreeMap 会完全忽略键的自然顺序（即 Comparable 接口的实现），并始终使用该 Comparator 来对键进行排序。Comparator 的优先级高于 Comparable。",
    "source": "文档中「比较器的使用」-「6. Comparator与TreeMap的关系」部分",
    "hint": "文档中明确指出：“如果指定了Comparator，则TreeMap会使用该比较器来对键进行排序，而不依赖于键本身的compareTo()方法。”"
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            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  